patch 8.2.4148: deleting any mapping may cause <ScritpCmd> to fail

Problem:    Deleting any mapping may cause <ScritpCmd> to not set the script
            context.
Solution:   Only reset last_used_map if it is the deleted mapping.
            (closes #9568)
diff --git a/src/proto/getchar.pro b/src/proto/getchar.pro
index 2d791e5..a034257 100644
--- a/src/proto/getchar.pro
+++ b/src/proto/getchar.pro
@@ -53,5 +53,5 @@
 int fix_input_buffer(char_u *buf, int len);
 int input_available(void);
 int do_cmdkey_command(int key, int flags);
-void reset_last_used_map(void);
+void reset_last_used_map(mapblock_T *mp);
 /* vim: set ft=c : */